Inductance coil



April 17, 1928.

E. R. MORTON.

INDUCTANCE con.

Filed NOV. 4, 1924 Patented Apr. 17, 1928.

UNITED STATES PATENT OFFICE.

EDMUND R. MORTON, OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC COM- IPANY, INCORPORATED, OF NEW YORK. N. Y., A CORPORATION OF NEW YORK.

INDUCTANCE COIL.

Application filed November 4, 1924. Serial No. 747,711.

This invention relates to inductance coils and more particularly to the ironclad inductance coils used in circuit loading.

The object of this invention is to provide an economical and efficient method for mechanically fastening the two halves of ironclad inductance coils together.

The coils of the particular type to which this invention is applicable consist of the toroidal ironclad type of loading coil in which an inductance winding is embedded in and-between two annular rings of iron dust material, which not only greatly resists drilling for fastening thetwo halves of the ring together, but also destroys the drills by grinding them away. There is also danger of cracking and checking in the material during drilling. This invention provides a means for fastening the two halves of the ring together without drilling or otherwise altering the material of the ring, by inserting a short length of metal tubing in the center of the ring and expanding its ends until they clamp the ring halves secure y. In a similar manner the ring halves may be fastened together by means of a larger tube spun over the outer edge of the rin Referring to the drawing in which like characters represent like parts,

Fig. 1 is a cross section of the ironclad inductance coil showing one form of this invention;

Fig. 2 is a plan view of the-same:

Fig. 3 is a partial cross section of the coil showing another form of this invention; and

Fig. 4 is a partial cross section of this invention as applied to an iron shielded coil.

Referring particularly to Figs. 1 and 2. numeral designates the inductance winding embedded in the core material. which is formed into two rings 2 and 3 of semi-circular cross-section and grooved to enclose the winding 1 as the two halves 2 and 3 fit together at their flat faces, forming a toroid. l/Vhile various kinds of magnetic material may be employed in the core. ithasgener' ailly been found preferable to employ initially plastic-material comprising iron dust united with a suitable compound in the manner disclosed by U. S. Patent N0. 1,274,952 of August 6. 1918. The difiiculties encountered in drilling through this material in order to join the two rings 2 and 3 together, are obvious. For this purpose, a short length of preferably seamless copper or brass tubing 4 is inserted in the central opening of the coil and its ends expanded and spun over until they are firmly engaged to the outer faces of the ring in the manner of an eyelet or a grommet as shown in Fig. 1.

Fig. 3 illustrates a modification in which. the two halves of the coil are clamped by an external tube 5 spun over at its edges to firmly engage the outer surface of the ring. Fig. 4 illustrates a method of enclosing the coil in a soft iron screen whereby the two ring-shaped shells 6 and 7 are also held in place by the grommet 4. It is obvious that the two shields 6 and 7 may be similarly clamped with the two coil rings 2 and 3 by means of an external ring 5 in a manner similar to that shown in Fig. 3.

It. is understood that the foregoing specification describes a preferred embodiment of my invention and that changes may be cffccted in the form, construction and propor-' tion of the same without departing from the spirit of this invention within the scope of the appended claims.

hat is claimed is:

1. In combination, a core made up of a plurality of parts which cooperate to form a chamber. a coil in said chamber. and a tubular member axially arranged with respect to said core and having its ends formed to approximate the contour of said core parts, and thereby clamp the core parts together.

2. In combination, a toroidal core in two parts which cooperate to form a chamber. a coil in said chamber, and a tubular member axially arranged with respect to said core and having its ends spun over to engage the respective core parts and thereby provide a unitary core structure.

3. In' con'tbination. a toroidal core in two parts which cooperate to form a chamber, a coil in sa d chamber, and a grommet inserted through the center of the core and having its ends spun over the halves of the core.

In witness whereof, I hereunto subscribe my name this 3rd day of November A. D.. 1924.

EDMUND n. MORTON. 

